Fuel and air

P028A — Charge Air Cooler Cooling Fan Control Circuit Open

Severity: medium Drive with care, to a shop

What P028A means

On turbocharged engines, the control unit commands an electric fan that helps cool the charge air cooler (intercooler). P028A means the ECM found an open circuit, or no proper response, in that fan's control circuit. Without good cooling, intake air gets hotter and the ECM may limit power. Note that some references list this code as reserved, so confirm its exact meaning for your vehicle.

Symptoms

  • Check Engine light on
  • Reduced engine power
  • Sluggish acceleration
  • Rough running
  • Unusual noise from the fan, or the fan not running

Possible causes

  1. Open circuit or poor connection in the fan control wiring
  2. Failed charge air cooler fan motor
  3. Damaged or corroded connector
  4. Faulty fan relay or fan control module
  5. ECM fault (rare)
  6. Code may be undefined in some standards, so the meaning may differ

How to diagnose

  1. Scan all codes and freeze frame data, looking for related boost or temperature codes
  2. Inspect the fan, connector and harness for damage, chafing and corrosion
  3. Check the fan fuse and relay
  4. Command the fan on with a scan tool and see if it responds
  5. Use a multimeter to check power, ground and the control signal at the connector
  6. Test the harness for an open between the fan and the ECM
  7. Check the fan motor resistance and current draw
  8. Compare the code with the manufacturer's wiring diagram and service info

Common fixes

  • Repair the wiring and replace damaged connectors
  • Replace the fan motor
  • Replace the relay or fan control module
  • Clean the contacts, clear the code and verify it does not return

Questions and answers

What does P028A mean?

It usually indicates an open in the charge air cooler fan control circuit. Some sources list it as reserved, so check the definition for your specific vehicle.

Can I drive with P028A?

Short trips at gentle throttle are usually fine, but power may be reduced. Avoid heavy loads and get it diagnosed soon.

Where should I start diagnosing it?

Check the fuse, relay, connector and wiring of the fan, then command it on with a scan tool. Bad connections and broken wires are common causes.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.